Thread tensioning member in welded header structure

ABSTRACT

An improved header assembly and corresponding port assembly comprising a tensioning member, wherein the tensioning member is isolated and separate from the weld portion and is adapted to place a threaded portion between the header assembly and port assembly in tension and maintain such tension, and thus relieve tension from the weld, before and after welding, thereby increasing the lifespan of the header and port assemblies.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Continuation application of U.S. Non-Provisionalpatent application Ser. No. 13/735,657, filed Jan. 7, 2013, which claimspriority under 35 U.S.C. 119(e) to U.S. Provisional Application61/583,478, filed Jan. 5, 2012, the entire contents of which are herebyincorporated by reference.

TECHNICAL FIELD

The present invention relates to welded header structure assemblies andmethods of making same.

BACKGROUND

Many pressure transducer assemblies are configured to include a headerportion that houses a sensing element and a port portion, wherein theheader is attached to the port portion. The attachment between theheader and port portions enable electrical connection between thesensing element and the remaining electronic components within thepressure transducer assembly. The header/port attachment serves to sealand contain the pressure media in the manifold/pipe, etc., whileisolating the electrical components from the media, and allowingassembly of the electronics to the pressure sensing sub assembly.

Typically, the header portion is welded to the port portion and, in manyembodiments, the header portion comprises a threaded section that mateswith a corresponding threaded section on the port portion, asillustrated in FIG. 1. The threads are provided to take the load off thewelded section. In use, the welded portion may experience stresses dueto internal pressures in the design. These stresses include the hoopstress or tangential stress, and radial stress.

It was once believed that the thread would aid in removing the tensilestress from the weld area. However, several micrographs of experimentaland production designs indicate that the threads may become disengagedduring welding, thereby placing tensile stress on the welded area. Theweld is typically an electron beam weld, and as the material melts toform the weld, any preload on the structure may be removed.Consequently, this increases the stress on the welded portion andreduces the fatigue life of the pressure transducer assemblyconsiderably.

BRIEF SUMMARY

The various embodiments of the present invention provide a transducerstructure, comprising a header assembly comprising a first threadedportion, a port assembly comprising a second threaded portion thatcorrespondingly mates with the first threaded portion, an access pointat a header assembly-port assembly interface, and a tensioning memberisolated from the access point, wherein the tensioning member is adaptedto maintain tension between mated first and second threaded portionsduring welding.

Other embodiments provide a transducer structure, comprising a headerassembly comprising a first threaded portion, a port assembly comprisinga second threaded portion that correspondingly mates with the firstthreaded portion, a weld at an interface between the header assembly andport assembly, and a tensioning member isolated from the weld, whereinthe tensioning member is adapted to maintain tension between mated firstand second threaded portions during welding.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a prior art embodiment of a header and port assemblywithout a tensioning member.

FIG. 2 illustrates a prior art embodiment of a header and port assemblyprior to welding with threads engaged and locked in tension.

FIG. 3 illustrates a prior art embodiment of a header and port assemblyafter welding with threads unlocked.

FIG. 4 illustrates an exemplary embodiment of a header and port assemblyof the present invention comprising a tensioning member.

FIG. 5 illustrates another exemplary embodiment of a header and portassembly of the present invention comprising a tensioning member.

FIG. 6 illustrates yet another exemplary embodiment of a header and portassembly of the present invention comprising a tensioning member.

FIG. 7 illustrates exemplary embodiments of tension members inaccordance with the present invention.

DETAILED DESCRIPTION

Although preferred embodiments of the invention are explained in detail,it is to be understood that other embodiments are contemplated.Accordingly, it is not intended that the invention is limited in itsscope to the details of construction and arrangement of components setforth in the following description or illustrated in the drawings. Theinvention is capable of other embodiments and of being practiced orcarried out in various ways. Also, in describing the preferredembodiments, specific terminology will be resorted to for the sake ofclarity.

It must also be noted that, as used in the specification and theappended claims, the singular forms “a,” “an,” and “the” include pluralreferents unless the context clearly dictates otherwise.

Also, in describing the preferred embodiments, terminology will beresorted to for the sake of clarity. It is intended that each termcontemplates its broadest meaning as understood by those skilled in theart and includes all technical equivalents which operate in a similarmanner to accomplish a similar purpose.

By “comprising” or “containing” or “including” is meant that at leastthe named compound, element, particle, or method step is present in thecomposition or article or method, but does not exclude the presence ofother compounds, materials, particles, method steps, even if the othersuch compounds, material, particles, method steps have the same functionas what is named.

It is also to be understood that the mention of one or more method stepsdoes not preclude the presence of additional method steps or interveningmethod steps between those steps expressly identified. Similarly, it isalso to be understood that the mention of one or more components in adevice or system does not preclude the presence of additional componentsor intervening components between those components expressly identified.

Referring now to the drawings, in which like numerals represent likeelements, exemplary embodiments of the present invention are hereindescribed. It is to be understood that the figures and descriptions ofthe present invention have been simplified to illustrate elements thatare relevant for a clear understanding of the present invention, whileeliminating, for purposes of clarity, many other elements found intypical pressure sensor assemblies and chip-package assemblies andmethods of making and using the same. Those of ordinary skill in the artwill recognize that other elements are desirable and/or required inorder to implement the present invention. However, because such elementsare well known in the art, and because they do not facilitate a betterunderstanding of the present invention, a discussion of such elements isnot provided herein.

Exemplary embodiments of the present invention provide an improvedheader assembly and corresponding port assembly comprising a tensioningmember. The tensioning member is isolated and separated from a weldportion connecting the header and port at an interface and is adapted toplace a threaded portion connecting the header and port in tension andmaintain such tension before, during, and after welding, therebyincreasing the lifespan of the header and port assemblies.

Referring to FIG. 1, there is shown a prior art embodiment of a headerassembly 105 connected to a corresponding port assembly 110. Asillustrated, the header assembly 105 comprises an isolation diaphragm115 adapted to receive an incoming pressure stream, and a sensing dieplate 120 adapted to submit a signal indicative of the incoming pressurestream. The header assembly 105 may be inserted into a correspondingport assembly 110 via corresponding threading portions. For example, theheader assembly 105 may comprise a first threaded portion, and the portassembly 110 may comprise a second threaded portion that correspondinglymates with the first threading portion. To connect the header assembly105 to the port assembly 110, the header assembly 105 may be threadedinto the port assembly 110 such that the first threaded portion of theheader assembly 105 engages the second threaded portion of the portassembly 110, thereby creating a threaded portion 125. To furthersupport the connection between the header assembly 105 and the portassembly 110, a connecting weld 130 is applied at a header-portinterface.

Referring to FIGS. 2 and 3, there is shown sample prior art embodimentsof a header assembly and corresponding port assembly before and afterwelding, respectively. To connect the header assembly to thecorresponding port assembly, a first threaded portion on the headerassembly engages a second threaded portion on the port assembly. Thefirst threaded portion is torqued onto the second threaded portion untilit engages a thread stop. Once the thread stop is engaged, itconsequently imparts tension to the first and second threaded portions.After threading, it may be desirable to weld the header assembly to theport assembly at a location substantially adjacent the thread stop,which may consequently compromise the tension between the first andsecond threaded portions. To securely connect the header assembly to theport assembly, however, it is useful for the first and second threadedportions to remain in tension. If the tension between the first andsecond threaded portions is compromised, additional stress may becarried by the weld joint, which may reduce the lifespan of theassembly, as further described below.

To further secure the header assembly to the port assembly a weld istypically made at an external access point located between the headerassembly and port assembly at an interface therebetween. The weldingprocess, however, often times compromises the tension between the firstand second threaded portions. Specifically, the header and portassemblies are often constructed of metals having melting points lowerthan or around the same temperature as the welding temperature. In manyprior art embodiments, the thread stop is located near the location ofthe weld. This close proximity often times causes the thread stop tomelt during welding, which consequently compromises the tension betweenthe engaged threaded portions. When the tension between the first andsecond threaded portion is compromised, the tension is transferred tothe welded portion, which increases the likelihood of crack propagationand consequently reduces the lifespan of the overall assembly.

Thus, there is a need to create a header assembly and corresponding portassembly that may be constructed of metals having lower or substantiallysimilar melting temperatures as the welding temperature, can withstandstress caused by the act of welding, and be able to maintain the tensionbetween engaged threaded portions of the header and port assembliesbefore, during, and after welding even if the thread stop is compromisedby melting. In exemplary embodiments of the present invention, this isaccomplished by utilizing a tensioning member that is separate andisolated from an access point where the weld is located. The tensioningmember absorbs stress caused by welding and works to effectivelymaintain the tension within the engaged threaded portions therebymaintaining the integrity of the overall structure.

Referring to FIG. 4, there is shown an exemplary embodiment of a headerassembly 405 and a corresponding port assembly 410. In the variousembodiments of the present invention, the header assembly 405 comprisesa tensioning member 415 and a threaded portion that connects to a matingthreaded portion on the port assembly 410. To connect the headerassembly 405 to the port assembly 410, the threaded portion of theheader assembly 405 is torqued onto the mating threaded portion on theport assembly 410. During said torquing, the tensioning member 415 isslightly deformed, which subsequently imparts tension to the threadedportion 425. The tensioning member 415 acts as a crush ring or a spring,and thus locks the threaded portion 425 in tension, and this tension ismaintained before, during, and after welding the header assembly 405 tothe port assembly 410.

As further illustrated in FIG. 4, there is an access point 420 at aheader assembly-port assembly interface. This access point 420 enables auser to weld the header assembly and port assembly together. Therefore,the access point 420 may also be the weld location. As illustrated inFIG. 4, the tensioning member 415 is separate and isolated from theaccess point 420. This separation and isolation from the access point420 is important as it enables the preloaded tension applied to thethreaded portion 425 via the tensioning member 415 to be maintainedduring the welding of the header assembly to the port assembly at theaccess point 420, therefore providing a distinct advantage over priorart embodiments. Further, the isolation of the tensioning member 415from the access point 420 prevents the tensioning member 415 from beingcompromised by melting during welding.

Additionally, in an exemplary embodiment, the header assembly 405 maycomprise a first threaded portion 445 and a first thread stop 430. Theport assembly 410 comprises a complimentary second threaded portion 450and a complimentary second thread stop 435. The header assembly 405 canbe threaded onto the port assembly 410 via the complimentary secondthreaded portion 450 located on the port assembly 410 to create a joinedthreaded portion 425. The header assembly 405 may be torqued onto theport assembly 410 until the first thread stop 430 engages the secondthread stop 435. Alternatively, the header assembly 405 may be torquedonto the port assembly 410 until the first and second threaded portions445/450 are substantially engaged as the first thread stop 430 andsecond thread stop 435 do not have to necessarily engage. It shall beunderstood that the thread stop locations may be adjusted for variousimplementations.

As the header assembly 405 is threaded onto the port assembly 410, thetensioning member 415 is deformed or compressed within a tensioningregion 440. This deformation or compression “loads” the tensioningmember 415, which consequently can maintain the tension within thethreaded portion 425 during welding. In certain implementations, theaccess point 420 where the weld is carried out is substantially near thefirst thread stop 430, and the second thread stop 435 if the first andsecond threaded portions 445/450 are completely engaged. Thus, if thewelding temperature exceeds or is substantially near the melting pointof the header assembly 405 or port assembly 410 materials, it may meltthe thread stops. In prior art embodiments, this melting wouldcompromise the tension between the first and second threaded portions445/450. However, because the tensioning member 415 is isolated from theaccess point 420, and thus the welding region, the integrity of thetensioning member 415 is maintained throughout the welding process,which consequently maintains the tension between the first and secondthreaded portions 445/450.

There are many internal locations where the tensioning member 415 may beplaced relative to the threaded portion 425 and access point 420. Asillustrated in FIG. 4, the tensioning member 415 may be placed betweenthe threaded portion 425 and the access point 420 at a distance that isseparate and isolated from the access point 420. In alternativeembodiments, and as illustrated in FIG. 5, the tensioning member 415 maybe opposite the threaded portion 425 and the access point 420. It shallbe understood that the location of the tensioning member 415 is notlimited to the placements illustrated in FIGS. 4 and 5. The tensioningmember 415 may be placed in other locations depending on the header andport assembly design. For example, in other embodiments, the tensioningmember 415 may be placed towards the front of a header assembly, therebyforming a compression of the header thread in the direction towards thetop of the header assembly. In most embodiments, however, the tensioningmember is an internal component and is isolated and separate from theaccess point to sufficiently maintain the tension within the threadedportion before, during, and after the weld.

Further, as illustrated in FIGS. 4 and 5, the tensioning member 415 maybe integrally machined as part of the header assembly 405 or, inalternative embodiments, the tensioning member may be integrallymachined as part of the port assembly 410. As illustrated in FIG. 6, thetensioning member 415 may be a separate, stand-alone tensioning member415 disposed between the header assembly 405 and port assembly 410.Additionally, the tensioning member 415 may be of various shapes anddesigns, for example but not limited to, a semicircular or a saw toothprofile, or a spring or coil-like profile. FIG. 7 illustrates exemplaryembodiments of tensioning members. One skilled in the art willappreciate that the appropriate tensioning member is dependent upon thespecific application. For example, the tensioning member may be a solidtensioning ring, or a tensioning ring with a plurality of gaps to enableair or fluid passage though the unit if so desired.

It will be apparent to those skilled in the art that modifications andvariations may be made in the apparatus of the present invention withoutdeparting from the spirit or scope of the invention. It is intended thatthe present invention cover the modification and variations of thisinvention provided they come within the scope of the appended claims andtheir equivalents.

What is claimed is:
 1. A method, comprising: providing a header assemblycomprising a first threaded portion; providing a port assemblycomprising a second threaded portion configured to mate with the firstthreaded portion of the header assembly; providing a tensioning memberadapted to maintain tension between the first threaded portion and thesecond threaded portion; mating the header assembly with the portassembly by engaging the first threaded portion with the second threadedportion; pre-loading, by the tensioning member, a tension between thefirst threaded portion and the second threaded portion; and securelyconnecting, while maintaining pre-loading tension, a portion of theheader assembly to a portion of the port assembly at an interfacebetween the header assembly and the port assembly, wherein securelyconnecting the portion of the header assembly to the portion of the portassembly comprises applying a weld at an interface between the headerassembly and the port assembly.
 2. The method of claim 1, wherein theheader assembly comprises a pressure sensor.
 3. The method of claim 1,wherein the header and port assemblies are constructed of metals havinglower or substantially similar melting temperatures as a temperature ofthe weld.
 4. The method of claim 1, wherein the weld is an electron beamweld.
 5. The method of claim 1, wherein pre-loading comprises applying atorque between the header assembly and the port assembly.
 6. The methodof claim 1, wherein the tensioning member is location- andtemperature-isolated from interface between the header assembly and theport assembly.
 7. The method of claim 1, wherein the pre-loading isoperable to maintain tension before, during, and after the securelyconnecting.
 8. The method of claim 1, wherein pre-loading compresses thetensioning member between the header assembly and the port assembly. 9.The method of claim 1, wherein the tensioning member is integrallymachined as part of the header or port assembly.
 10. The method of claim1, wherein the tensioning member is a solid ring.
 11. The method ofclaim 1, wherein the tensioning member is a ring comprising a pluralityof holes.
 12. A method, comprising: providing a header assemblycomprising a first threaded portion; providing a port assemblycomprising a second threaded portion configured to mate with the firstthreaded portion of the header assembly; providing a tensioning memberadapted to maintain tension between the first threaded portion and thesecond threaded portion; mating the header assembly with the portassembly by engaging the first threaded portion with the second threadedportion; pre-loading, by the tensioning member, a tension between thefirst threaded portion and the second threaded portion; and welding,while maintaining the pre-loading tension by the tensioning member, aportion of the header assembly to a portion of the port assembly at aninterface between the header assembly and the port assembly.
 13. Themethod of claim 12, wherein the header assembly comprises a pressuresensor.
 14. The method of claim 12, wherein the header and portassemblies are constructed of metals having lower or substantiallysimilar melting temperatures as a temperature of the weld, and whereinthe tensioning member is not melted during the welding.
 15. The methodof claim 12, wherein the welding comprises electron beam welding. 16.The method of claim 12, wherein pre-loading comprises applying a torquebetween the header assembly and the port assembly.
 17. The method ofclaim 12, wherein the tensioning member is isolated from interfacebetween the header assembly and the port assembly.
 18. The method ofclaim 12, wherein the pre-loading is operable to maintain tensionbefore, during, and after the welding by compressing the tensioningmember between the header assembly and the port assembly.
 19. The methodof claim 12, wherein the tensioning member is integrally machined aspart of the header or port assembly.